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ELBGTRIGAL SIGNALING APPARATUS. No. 252.288. 'Patented Jan. 10,1882.

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C. E. BUELL J. E. BUEL,l PLPGTPIGAL SIGNALING APPARATUS.

No.. 252,288. Patented JAA. 10.1382.

Wwassas Mwexms e tactlplate l to contact-plate 2.

- UNITED STATES PATENT OFFICE.

C EAELES 'E, EUELL, 0E NEW HAVEN,CONNECTICUT,` AND J. FREDERICK BUEL,0E WCBUEN, MASSACHUSETTS 5 SAID CHAS. E. BUELL ASSIGNCE, BY MESNE ASSIGNMENTS, To THE UNITED STATES TELEPHONE` MANU-` FACTURING COMPANY, oE NEW "YORK, N. Y.

ELECTRICAL sleNA-Llno `APPARATUS@` t SPECIFICATION formingy part of Letters Patentl No. 252,288, dated January 1o, 1882.

Application led January 21, 1880.

to tricit) `,p and it consists Ain combining a call-bellv magnet and switch with receiving telephonestatons in such a manner thatconversation by telephone can neither be overheard nor interrupted. f f

In the accompanying drawings, which form a part of this specification, the same letters V and 1i gures referto corresponding parts in each.

Eigure 1 is a plan View of the call-bell mag net M, with neutral armature A, having a pro- ,zo'jectiom V, thereomand arranged in relation to the switch D and pin P,so that when the armature is not attracted the projection V comes between the end of the switch D and pin P and t obstructs the moving ofthe switch D 'from con- When the armature is 'attracted the projection V is' moved p out of the path oftliefswitch D, admitting of its being turned from plate lfto plate 2, Wherebyfthe telephone T is interposed in the main 3o circuit. `Thecircuitis then closed in the dii rection ofthe arrows No l-say from the linewire to the transmitter F, thence over wire c to the coils of the mag-net, thenceoverwire 'u/ to the switch D, through the Switch to the divided contactlplate2, thence to the telephone T over wire t, and from the telephone over wire t to contact-plate `1, and on" to the lineat the right. The moving of the switch D from plate l to plate 2 also serves to close the circuit of 2, from battery B, through wire c, to the pri,- tnary coil of the transmitter F, thence over wire YIfv to the switch, over the switch to the .divided 'plate 2, and thence back to the `bat- 4 5 tery over wire c2. The local-battery circuit is open when the switch-lever is not in Contact with button No. 2. The contact-plate 3 1is arranged with a ground-wire, g, and servesthe `The secondary coil of the 'transmitter may purpose ot a signaling key as the switch D passes in contact therewith to make operative a differential receiving apparatus at a central station to indicate or sound a `detinitecall or signal by varying the tension of the main cir` cuit to a detinitedegree foreach station. The batter)1 Band transmitter Fare well-known elements. As the battery charging 'the main circuit is withdrawn when conversation is being carried on through the telephones, and as the switch Dcannot beturnedafte'r the battery is removed and the line is in condition for telephonicV communication, other stations than those already lconnected for telephoning cannot interruptor overhear the communications which are being transmitted, and as each sta-- tion Ais arranged to signal its respective call when its switch istnrned, no station can int out the fact being known at the central station.

7o be included in the telephone branch circuit in l the ordinary manner without departing from our invention.

Fig, 2 is a plan view of the magnet M on a movable base, havin g'aholecut therein.,through which the pin P passes. The pin P is disconnected from the base, and is so arranged with relation to the armature A that it will come in Contact with.the projection V it' the base is turned when the armature is not attracted, and prevents the telephone T from being `interposed in the main circuit after the .battery which charges the main circuit is withdrawn;

Fig; 3 is a side elevation of the switch D as a part o'f a telephone-holder, and is arranged in relation to the armature A, as shown and i described. 4o the local battery B, as indicated by arrows No.

Fig. 4 is a plan view of the magnet M and armature A upon a movable base, and ar ranged iin their relation to the pin P so that ,when the base is turnedwhile the armature is attracted-the pin P will hold the armature in contact with the screw or point C but if the base is turned when the armature is not attracted the pin P serves to hold the armature in contact with the screw or point U2. When terposeits telephone in the main circuit With- 'l l the base is turned to plate 2, the telephone is Yinterposed in the main circuit. The moving of the base over the contact-plates a b c serves to transmit a signal by making and breaking the circuit. A given number of breaks of the circuit can bemade for each station. When the armature A is in contact with the point C2 the circuit is permanently closed by the dotted wire F.

Fig. 5 is a side elevation of a cross-section of a call-bell electro-magnet, so constructed and arranged that the bell b covers the entire mechanism of the hammer, armature, and'connections except the projecting handle of the switch D. The bell P has a piece rigidly at-V tached to the inside surface thereof for the vhammer h to strike against.

Fig. 6 represents a cross-section of a side elevation of a moditied form of the call-bell and switch shown in Fig. 5 and described, a single-coil electro-magiiet, m, being used, and its core c, which protrudes through the base, being the support for the bell b.

Fig. 7 shows the bell b as covering the electro-magnet, switch, and connections, as shown in figures previously described.

The switch D and contact-pieces 1 2 3 can be detached from the .base which supports the call-bell without departing from theinvention; and when a press-buttoukey is employed, instead of the switch and contact-pieces shown, for calling a central station, a shield attached to the armature of the electro-magnet can be made to cover the press-button when the armature is in the position termed openand thereby prevent interference. A(Not shown.) The armatures can be attracted to the sid-es of the protruding cores of the electro-magnets and neutral or polarized armatures be einployed. Y

XVe claimf- 1. In atelephone-station apparatus, the combination of the following elements, to wit: 'a main electric circuit, an independent branch circuit including a telephone, and switch devices, substantially such as described, wherebythe branch circuit may be interposed in and withdrawn from the main circuit, essentially as herein set forth.

2. The combination, with a charged main t telephone-line and a station telephone-circuit,

of a switch and an attracted armature of the electromagnet included in the said circuit, the switch and the armature being arranged to be interlocked with each other when the attraction of the armature has ceased by the removal of the charging-batteriesfrom the main circuit, substantially as described, whereby the teleplionecircuit is prevented from being interposedy in the main circuit after the charging-batteries are removed from the main circuit, as set forth.

3. The combination, with a main electric cir cuit, of a telephone apparatus, substantially as described, provided with a switch and connections arranged to interpose a telephone and transmitter in the said main line, and to simultaneously close a local battery'througli said transmitter and produce a call or signal upon said main line, as set forth.

4. The combination, ina telephone-station apparatus, ot' a callbell electro magnet included ina main circuit, a telephone, and a transmitter in a branch circuit, with a switch and connections, substantially such ,as described,` whereby the telephone branch circuit may be interposed in the main circuit with the said call-bell electro-magnet, as set forth.

.5. The combination, with a chargednmain electric circuit, including a telephone-station of a telephone apparatus provided with Y a switch, an electro-magnet, and an attracted armature, said ,armature being arranged` to lock the-switch when the vattraction ceases to prevent it being turned to interposc the telephone in the main electric circuit, as set forth, whereby the central ofce can lock out stations not already interposed by removing the charging-batteries from the main line.

' `6. The combination, with a single-coil electro-magnet, of a bell attached to and supported by the rod or core which retains the helix of the magnet, substantially as described.

7. The combination, with a call-bell ,electro-Ai magnet, of a stationary bell arranged to cover ythe electro-magnet and armature, and having a projecting piecerigidly attached to its inner surface to receive the blows of the armature or hammer, substantially as described'.

CHARLES E. BUELL. J. FREDERICK BUEL.

Witnesses:

T. MAnviN PARKER, WM. R. McINTosn. 

